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Detached backyard ADU built by a Renovation Bridge contractor in the Bay AreaAlways free to homeowners
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ADU costin the Bay Area

Rough size

Typical range

$150,000$520,000

All ADU types, from garage conversions to detached new builds. Based on what vetted Bay Area contractors are charging, including design and permits. Updated 2026 Q2.

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What moves the number

The type of ADU is the biggest lever on price — a garage conversion reuses the structure you already have, while a detached new build is a small house from the ground up.

Garage conversion

Convert your existing garage

$150K – $275K

Prefab ADU, installed

10 models, 390–1,200 sq ft · fixed pricing

$195K – $305K

Attached new build

Connected to your main home

$185K – $420K

Detached new build

Standalone unit on your lot

$220K – $520K

Bay Area-wide ranges — pick your county above and these adjust.

How you get the real number

The ranges above are honest, but no formula knows your lot, your home's age, or your city's permit desk. Here's how we get you a number that's actually yours:

Tell us about your project

A few quick questions — project type, scope, size, timeline. About 2 minutes, no documents needed.

Get your true number on a quick call

We look at your address and your goals, then give you a real range based on what vetted contractors are charging for projects like yours — not a formula, and never a sales pitch.

Meet up to 3 vetted contractors — if you want to

When you're ready, we introduce you to contractors we've vetted for licenses, insurance, and past work — and stay in your corner while you compare bids. Free, no obligation.

Typical timeline: 6–13 months from design to move-in, including permits.

Good questions

Why is the range so wide?

Because "ADU" covers everything from converting an existing garage to building a standalone 1,200 sq ft home. Size, build type, site conditions (slope, utility distance), and your city's permit requirements each move the number by tens of thousands. That's why we give you a real number for your specific address on a call — not a formula.

Does the price include permits and design?

The ranges above are all-in project budgets: construction plus soft costs like architecture, engineering, and permits. In the Bay Area, soft costs on an ADU typically add 15–20% on top of construction — we include that so you aren't surprised later.

How does Renovation Bridge make money if it's free for me?

Contractors pay us to be matched with serious homeowners. You never pay us anything, and your price is the same as going to the contractor directly. We only work with contractors we've vetted — licenses, insurance, references, and past work.

How accurate is the number I get on the call?

We look at your address, lot, and project goals, then give you a range based on what vetted contractors are actually charging for comparable Bay Area projects right now. It's a planning number, not a bid — your final price comes from the contractors you meet, and meeting them through us is free.

Ready for your exact number?

Two minutes of questions, then a real number for your address — from people who talk to Bay Area contractors every day.

Get my exact number — free

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